United States Dollar  
  Figures in millions unless otherwise stated 2018      2017   
19. INVENTORIES          
  Gold-in-process and stockpiles 325.0      305.4   
  Consumable stores 176.5      220.9   
  Total inventories 501.5      526.3   
  Heap leach and stockpiles inventories included in non-current assets4 (133.3)     (132.8)  
  Total current inventories5 368.2      393.5   
  4 Heap leach and stockpiles inventories will only be processed at the end of life-of-mine.
  5 The cost of consumable stores consumed during the year and included in cost of sales amounted to US$280.0 million (2017: US$346.7 million).